osd: don't send stale hb msgr's addresses in MOSDBoot

osd: don't send stale hb msgr's addresses in MOSDBoot

See comments in the ticket for the RCA.

NOTE: we can't just hold a reference to what `get_myaddrs()`
returns as the `safe_item_history` is involved:

```cpp
template<class T>
class safe_item_history {
  //...
  T *current = nullptr;

  // ...
  const T& operator=(const T& other) {
    std::lock_guard l(lock);
    history.push_back(other);
    current = &history.back();
    return *current;
  }
```

Fixes: https://tracker.ceph.com/issues/58915
Signed-off-by: Radosław Zarzyński <rzarzyns@redhat.com>